var $ = {
    canvas: null,
    ctx: null,
    canvas2: null,
    ctx2: null,
    colors: {
      sky: "#D4F5FE",
      mountains: "#83CACE",
      ground: "#8FC04C",
      groundDark: "#73B043",
      road: "#606a7c",
      roadLine: "#FFF",
      hud: "#FFF"
    },
    settings: {
      fps: 60,
      skySize: 120,
      ground: {
        size: 350,
        min: 4,
        max: 120
      },
      road: {
        min: 76,
        max: 700,
      }
    },
    state: {
      bgpos: 0,
      offset: 0,
      startDark: true,
      curve: 0,
      currentCurve: 0,
      turn: 1,
      speed: 27,
      xpos: 0,
      section: 50,
      car: {
        maxSpeed: 50,
        friction: 0.4,
        acc: 0.85,
        deAcc: 0.5
      },
      keypress: {
        up: false,
        left: false,
        right: false,
        down: false
      }
    },
    storage: {
      bg: null
    }
  };
$.canvas = document.getElementsByTagName('canvas')[0];
$.ctx = $.canvas.getContext('2d');
$.canvas2 = document.createElement('canvas');
$.canvas2.width = $.canvas.width;
$.canvas2.height = $.canvas.height;
$.ctx2 = $.canvas2.getContext('2d');
window.addEventListener("keydown", keyDown, false);
window.addEventListener("keyup", keyUp, false);

drawBg();
draw();

function draw() {
setTimeout(function() {
  calcMovement();
 
  //if($.state.speed > 0) {
    $.state.bgpos += ($.state.currentCurve * 0.02) * ($.state.speed * 0.2);
    $.state.bgpos = $.state.bgpos % $.canvas.width;
   
    $.ctx.putImageData($.storage.bg, $.state.bgpos, 5);
    $.ctx.putImageData($.storage.bg, $.state.bgpos > 0 ? $.state.bgpos - $.canvas.width : $.state.bgpos + $.canvas.width, 5);
  //}
 
  $.state.offset += $.state.speed * 0.05;
  if($.state.offset > $.settings.ground.min) {
    $.state.offset = $.settings.ground.min - $.state.offset;
    $.state.startDark = !$.state.startDark;
  }
  drawGround($.ctx, $.state.offset, $.colors.ground, $.colors.groundDark, $.canvas.width);
 
  drawRoad($.settings.road.min + 6, $.settings.road.max + 36, 10, $.colors.roadLine);
  drawGround($.ctx2, $.state.offset, $.colors.roadLine, $.colors.road, $.canvas.width);
  drawRoad($.settings.road.min, $.settings.road.max, 10, $.colors.road);
  drawRoad(3, 24, 0, $.ctx.createPattern($.canvas2, 'repeat'));
  drawCar();
  drawHUD($.ctx, 630, 340, $.colors.hud);
 
  requestAnimationFrame(draw);
}, 1000 / $.settings.fps);
}

function drawHUD(ctx, centerX, centerY, color) {
var radius = 50, tigs = [0, 90, 135, 180, 225, 270, 315],
    angle = 90;

ctx.beginPath();
ctx.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);
ctx.lineWidth = 7;
ctx.fillStyle = 'rgba(0, 0, 0, 0.4)';
ctx.fill();
ctx.strokeStyle = color;
ctx.stroke();

for (var i = 0; i < tigs.length; i++) {
  drawTig(ctx, centerX, centerY, radius, tigs[i], 7);
}

// draw pointer
angle = map($.state.speed, 0, $.state.car.maxSpeed, 90, 360);
drawPointer(ctx, color, 50, centerX, centerY, angle);
}

function drawPointer(ctx, color, radius, centerX, centerY, angle) {
var point = getCirclePoint(centerX, centerY, radius - 20, angle),
    point2 = getCirclePoint(centerX, centerY, 2, angle + 90),
    point3 = getCirclePoint(centerX, centerY, 2, angle - 90);

ctx.beginPath();
ctx.strokeStyle = "#FF9166";
ctx.lineCap = 'round';
ctx.lineWidth = 4;
ctx.moveTo(point2.x, point2.y);
ctx.lineTo(point.x, point.y);
ctx.lineTo(point3.x, point3.y);
ctx.stroke();

ctx.beginPath();
ctx.arc(centerX, centerY, 9, 0, 2 * Math.PI, false);
ctx.fillStyle = color;
ctx.fill();
}

function drawTig(ctx, x, y, radius, angle, size) {
var startPoint = getCirclePoint(x, y, radius - 4, angle),
    endPoint = getCirclePoint(x, y, radius - size, angle)

ctx.beginPath();
ctx.lineCap = 'round';
ctx.moveTo(startPoint.x, startPoint.y);
ctx.lineTo(endPoint.x, endPoint.y);
ctx.stroke();
}

function getCirclePoint(x, y, radius, angle) {
  var radian = (angle / 180) * Math.PI;

  return {
    x: x + radius * Math.cos(radian),
    y: y + radius * Math.sin(radian)
  }
}

function calcMovement() {
var move = $.state.speed * 0.01,
    newCurve = 0;

if($.state.keypress.up) {
  $.state.speed += $.state.car.acc - ($.state.speed * 0.015);
} else if ($.state.speed > 0) {
  $.state.speed -= $.state.car.friction;
}

if($.state.keypress.down && $.state.speed > 0) {
  $.state.speed -= 1;
}

// Left and right
$.state.xpos -= ($.state.currentCurve * $.state.speed) * 0.005;

if($.state.speed) {
  if($.state.keypress.left) {
    $.state.xpos += (Math.abs($.state.turn) + 7 + ($.state.speed > $.state.car.maxSpeed / 4 ? ($.state.car.maxSpeed - ($.state.speed / 2)) : $.state.speed)) * 0.2;
    $.state.turn -= 1;
  }

  if($.state.keypress.right) {
    $.state.xpos -= (Math.abs($.state.turn) + 7 + ($.state.speed > $.state.car.maxSpeed / 4 ? ($.state.car.maxSpeed - ($.state.speed / 2)) : $.state.speed)) * 0.2;
    $.state.turn += 1;
  }
 
  if($.state.turn !== 0 && !$.state.keypress.left && !$.state.keypress.right) {
    $.state.turn += $.state.turn > 0 ? -0.25 : 0.25;
  }
}

$.state.turn = clamp($.state.turn, -5, 5);
$.state.speed = clamp($.state.speed, 0, $.state.car.maxSpeed);

// section
$.state.section -= $.state.speed;

if($.state.section < 0) {
  $.state.section = randomRange(1000, 9000);
 
  newCurve = randomRange(-50, 50);
 
  if(Math.abs($.state.curve - newCurve) < 20) {
    newCurve = randomRange(-50, 50);
  }
 
  $.state.curve = newCurve;
}

if($.state.currentCurve < $.state.curve && move < Math.abs($.state.currentCurve - $.state.curve)) {
  $.state.currentCurve += move;
} else if($.state.currentCurve > $.state.curve && move < Math.abs($.state.currentCurve - $.state.curve)) {
  $.state.currentCurve -= move;
}

if(Math.abs($.state.xpos) > 550) {
  $.state.speed *= 0.96;
}

$.state.xpos = clamp($.state.xpos, -650, 650);
}

function keyUp(e) {
  move(e, false);
}

function keyDown(e) {
  move(e, true);
}

function move(e, isKeyDown) {
if(e.keyCode >= 37 && e.keyCode <= 40) {
  e.preventDefault();
}

if(e.keyCode === 37) {
  $.state.keypress.left = isKeyDown;
}

if(e.keyCode === 38) {
  $.state.keypress.up = isKeyDown;
}

if(e.keyCode === 39) {
  $.state.keypress.right = isKeyDown;
}

if(e.keyCode === 40) {
  $.state.keypress.down = isKeyDown;
}
}

function randomRange(min, max) {
return min + Math.random() * (max - min);
}

function norm(value, min, max) {
return (value - min) / (max - min);
}

function lerp(norm, min, max) {
return (max - min) * norm + min;
}

function map(value, sourceMin, sourceMax, destMin, destMax) {
return lerp(norm(value, sourceMin, sourceMax), destMin, destMax);
}

function clamp(value, min, max) {
return Math.min(Math.max(value, min), max);
}

function drawBg() {
$.ctx.fillStyle = $.colors.sky;
$.ctx.fillRect(0, 0, $.canvas.width, $.settings.skySize);
drawMountain(0, 60, 200);
drawMountain(280, 40, 200);
drawMountain(400, 80, 200);
drawMountain(550, 60, 200);

$.storage.bg = $.ctx.getImageData(0, 0, $.canvas.width, $.canvas.height);
}

function drawMountain(pos, height, width) {
$.ctx.fillStyle = $.colors.mountains;
$.ctx.strokeStyle = $.colors.mountains;
$.ctx.lineJoin = "round";
$.ctx.lineWidth = 20;
$.ctx.beginPath();
$.ctx.moveTo(pos, $.settings.skySize);
$.ctx.lineTo(pos + (width / 2), $.settings.skySize - height);
$.ctx.lineTo(pos + width, $.settings.skySize);
$.ctx.closePath();
$.ctx.stroke();
$.ctx.fill();
}

function drawSky() {
$.ctx.fillStyle = $.colors.sky;
$.ctx.fillRect(0, 0, $.canvas.width, $.settings.skySize);
}

function drawRoad(min, max, squishFactor, color) {
var basePos = $.canvas.width + $.state.xpos;

$.ctx.fillStyle = color;
$.ctx.beginPath();
$.ctx.moveTo(((basePos + min) / 2) - ($.state.currentCurve * 3), $.settings.skySize);
$.ctx.quadraticCurveTo((((basePos / 2) + min)) + ($.state.currentCurve / 3) + squishFactor, $.settings.skySize + 52, (basePos + max) / 2, $.canvas.height);
$.ctx.lineTo((basePos - max) / 2, $.canvas.height);
$.ctx.quadraticCurveTo((((basePos / 2) - min)) + ($.state.currentCurve / 3) - squishFactor, $.settings.skySize + 52, ((basePos - min) / 2) - ($.state.currentCurve * 3), $.settings.skySize);
$.ctx.closePath();
$.ctx.fill();
}

function drawCar() {
var carWidth = 160,
    carHeight = 50,
    carX = ($.canvas.width / 2) - (carWidth / 2),
    carY = 320;

// shadow
roundedRect($.ctx, "rgba(0, 0, 0, 0.35)", carX - 1 + $.state.turn, carY + (carHeight - 35), carWidth + 10, carHeight, 9);

// tires
roundedRect($.ctx, "#111", carX, carY + (carHeight - 30), 30, 40, 6);
roundedRect($.ctx, "#111", (carX - 22) + carWidth, carY + (carHeight - 30), 30, 40, 6);

drawCarBody($.ctx);
}

function drawCarBody(ctx) {
var startX = 299, startY = 311,
    lights = [10, 26, 134, 152],
    lightsY = 0;

/* Front */
roundedRect($.ctx, "#C2C2C2", startX + 6 + ($.state.turn * 1.1), startY - 18, 146, 40, 18);

ctx.beginPath();
ctx.lineWidth="12";
ctx.fillStyle="#FFFFFF";
ctx.strokeStyle="#FFFFFF";
ctx.moveTo(startX + 30, startY);
ctx.lineTo(startX + 46 + $.state.turn, startY - 25);
ctx.lineTo(startX + 114 + $.state.turn, startY - 25);
ctx.lineTo(startX + 130, startY);
ctx.fill();
ctx.stroke();
/* END: Front */

ctx.lineWidth="12";
ctx.lineCap = 'round';
ctx.beginPath();
ctx.fillStyle="#DEE0E2";
ctx.strokeStyle="#DEE0E2";
ctx.moveTo(startX + 2, startY + 12 + ($.state.turn * 0.2));
ctx.lineTo(startX + 159, startY + 12 + ($.state.turn * 0.2));
ctx.quadraticCurveTo(startX + 166, startY + 35, startX + 159, startY + 55 + ($.state.turn * 0.2));
ctx.lineTo(startX + 2, startY + 55 - ($.state.turn * 0.2));
ctx.quadraticCurveTo(startX - 5, startY + 32, startX + 2, startY + 12 - ($.state.turn * 0.2));
ctx.fill();
ctx.stroke();

ctx.beginPath();
ctx.lineWidth="12";
ctx.fillStyle="#DEE0E2";
ctx.strokeStyle="#DEE0E2";
ctx.moveTo(startX + 30, startY);
ctx.lineTo(startX + 40 + ($.state.turn * 0.7), startY - 15);
ctx.lineTo(startX + 120 + ($.state.turn * 0.7), startY - 15);
ctx.lineTo(startX + 130, startY);
ctx.fill();
ctx.stroke();

roundedRect(ctx, "#474747", startX - 4, startY, 169, 10, 3, true, 0.2);
roundedRect(ctx, "#474747", startX + 40, startY + 5, 80, 10, 5, true, 0.1);

ctx.fillStyle = "#FF9166";

lights.forEach(function(xPos) {
  ctx.beginPath();
  ctx.arc(startX + xPos, startY + 20 + lightsY, 6, 0, Math.PI*2, true);
  ctx.closePath();
  ctx.fill();
  lightsY += $.state.turn * 0.05;
});

ctx.lineWidth="9";
ctx.fillStyle="#222222";
ctx.strokeStyle="#444";

roundedRect($.ctx, "#FFF", startX + 60, startY + 25, 40, 18, 3, true, 0.05);
}

function roundedRect(ctx, color, x, y, width, height, radius, turn, turneffect) {
var skew = turn === true ? $.state.turn * turneffect : 0;

ctx.fillStyle = color;
ctx.beginPath();
ctx.moveTo(x + radius, y - skew);

// top right
ctx.lineTo(x + width - radius, y + skew);
ctx.arcTo(x + width, y + skew, x + width, y + radius + skew, radius);
ctx.lineTo(x + width, y + radius + skew);

// down right
ctx.lineTo(x + width, (y + height + skew) - radius);
ctx.arcTo(x + width, y + height + skew, (x + width) - radius, y + height + skew, radius);
ctx.lineTo((x + width) - radius, y + height + skew);

// down left
ctx.lineTo(x + radius, y + height - skew);
ctx.arcTo(x, y + height - skew, x, (y + height - skew) - radius, radius);
ctx.lineTo(x, (y + height - skew) - radius);

// top left
ctx.lineTo(x, y + radius - skew);
ctx.arcTo(x, y - skew, x + radius, y - skew, radius);
ctx.lineTo(x + radius, y - skew);
ctx.fill();
}

function drawGround(ctx, offset, lightColor, darkColor, width) {
var pos = ($.settings.skySize - $.settings.ground.min) + offset, stepSize = 1, drawDark = $.state.startDark, firstRow = true;
ctx.fillStyle = lightColor;
ctx.fillRect(0, $.settings.skySize, width, $.settings.ground.size);

ctx.fillStyle =  darkColor;
while(pos <= $.canvas.height) {
  stepSize = norm(pos, $.settings.skySize, $.canvas.height) * $.settings.ground.max;
  if(stepSize < $.settings.ground.min) {
    stepSize = $.settings.ground.min;
  }

  if(drawDark) {
    if(firstRow) {
      ctx.fillRect(0, $.settings.skySize, width, stepSize - (offset > $.settings.ground.min ? $.settings.ground.min : $.settings.ground.min - offset));
    } else {
      ctx.fillRect(0, pos < $.settings.skySize ? $.settings.skySize : pos, width, stepSize);
    }
  }
 
  firstRow = false;
  pos += stepSize;
  drawDark = !drawDark;
}
}